Caption: Light micrograph of the freshwater protozoan Blepharisma sp., a ciliate of the order Hetero- trichida. Blepharisma has a strong undulating membrane (just visible here at upper left), which is used for feeding and movement. It feeds on bacteria & decaying organic matter. When feeding conditions are good it grows to an enormous size and these giants are sometimes seen to feed on their normal-sized relatives. Magnification unknown.